Apparatus for removing the product film from a revolving drum surface



Ann 15, 1952 c. o. LAVETT 2,592,914

APPARATUS FOR REMOVING THE PRODUCT FILM FRGM A REVOLVING DRUM SURFACEFiled Oct. 6, 1947 6 Sheets-Sheet l IN V EN TOR.

ATTOPIVZTYS i 1952 c. o. LAVETT 2,592,914

APPARATUS FOR REMOVING THE PRODUCT FILM FROM A REVOLVING DRUM SURFACEFiled 001;. 6, 1947 6 Sheets-Sheat 2 I INVENTOR.

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April 15, 1952 c. o. LAVETT ,59 ,914

. APPARATUS FOR REMOVING THE PRODUCT FILM FROM A REVOLVING DRUM SURFACEFiled Oct. 6, 1947 6 Sheets-Sheet 5 I Q i I INVENTOR. 9? aeozioe 95 Y 9a J A T Top/V5 April 15, 1952 Filed Oct. 6, 194'? C. O. LAVETT APPARATUSFOR REMOVING THE PRODUCT FILM FROM A REVOLVING DRUM SURFACE 6Sheets-Sheet 4 12 797 65 a I r03 INVENTOR G7 ATTORNEYIS April 15, 1952c. o. LAVETT 2,592,914

APPARATUS FOR REMQVING THE PRODUCT FILM FROM A REVOLVING DRUM SURFACEFiled Oct. 6, 1947 e Sheets-Sheet 5 IN VEN TOR.

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ATTORNEYS.

April 15, 1952 I c. o. LAVETT APPARATUS FOR REMOVING THE PRODUCT FILMFROM A REVOLVING DRUM SURFACE 6 Sheets-Sheet 6 Filed Oct. 6, 1947Patented Apr. 15, 1952 APPARATUS FOR- REMOVING THE PRODUCT FILM FROMAREVOLVING. DRUM SURFACE Charles 0. Lavett, Buffalo, N. Y., assignor toBlaw-Knox Company, Pittsburgh, Pa;

ApplicationOctober 6, 1947, Serial No; 778,076

8 Claims. (01. 159-41) This invention relates to apparatus for removingthe product film from a revolving drum surface and particularly to drumdryers where a liquid or semi-liquid product film is applied to arevolving hot drum surface for the purpose of drying or removingmoisture and where the dry product film is continually removed before a,full revolution of the drum has been completed. In such a drum dryer thecontinuous removal of the dry product film and the continuousapplication of a liquid or semi-liquid to the drum surface following theremoval of the dry product film makes the drying process continuous.

On atmospheric double drum dryers the present practice. is to use asingle knife for each drum. When plant scale operations permit, largesize dryers with drums up to 120 in length are preferred by the tradebecause of favorable proportionate dryer cost based on capacity as Wellas operating economy. The knife is clamped in a knife holder withsufficient exposure to obtain desired flexibility and to permitadjustments. The knife holder is usually mounted on the end' heads ateach end of the dryer, and means are also provided for exerting pressureupon the knife in contact with the drum'surface. The knife angle inrelation to the drum can be changed only by varying the distancebetweenthe drum and the knife holder or by varying the knife exposurebeyond the holder, each of which requires a substantial mechanicalalteration and requires complete shutdown of the dryer.

The knives for commercial sizes of drum dryers are usually thick andwhen new about 4-6" wide, varying with the size of the dryer, andslightly longer than the drum, one side of the knife being clamped toits holder while approximately of its width, with a sharp ground edge,extends beyond the holder;-

The'steam pressure in the drum or drums varies with the kind of productdried, on some products as high as 150' lbs. guage, equivalent to 366deg. F. Theheat from the drum plusthe friction between'thedrum surfaceand the knife in contact with the drum under pressure causes unequalexpansion of the knife which" tends to warp the knife edge. Since theknife holder turns in bearings on fixed centers; the knife is notself-alining and in clamping the knife in the holder extreme care mustbe exercised for proper exposure of the knife beyondthe holder. Thus,the knife edge must be parallel with the axis of the drum andrest asevenly aspossible over the entire length of the drum, otherwise,

when the knife edge is-adjusted' toward the drum, the portion of theknife edge first coming in contactwith the drum will be subjected togreater pressure and consequently wear faster and thus reduce theserviceable life of the knife edge. Grinding long knives to obtain'aperfectly straight edge is also difficult and further di ffi cultiesare encountered if the drum surface is not perfectly cylindrical orstraight or if the operator in changing knives neglects setting theadjustable drum exactly parallel to the non-adjustable drum on doubledrum dryers. The extreme care which must be exercised in obtainingproper relation between a single knife. blade and the drum surfacetherefore makes it difficult to properly remove a product film uniformlyover the entire length of a hot drum surface.

In an effort to alleviate to some degree the effects caused byinaccuracy and warping of the edge of a long knife, it is presentpractice to provide closely spaced knife adjusting screws and which areadjusted to apply pressure where necessary in order to hex or bend theknife so that its cutting edge will follow the drum as closely aspossible. Such adjustments are not satisfactory for while the bucklingorwarpin'gv is adjusted more uniformly to the drum surface the bucklingor warping isnot eliminated, and

therefore this buckling or warping still causesunequal pressure and wearof the knife edge. Such inequality of pressure occasionally scores or'even gouges the drum surface'where pressure is the greatest. Further,those parts of the knife edge which are subjected to the greaterpressure cutting qualities, however applying too much pressure causesthe knife to flex and bring the leading edge away from the drum and theheel or trailing edge in firmer contact with the drum surface, therebydestroying effective removal of the product film. When the leading edgeof the knife blade is so moved away fromthe drum surface, this edge alsotends to split the product film,--a1lowing part of such filmto passunder'the knife. This part of film left'ondrumwhere the knife is dull,may. at first be very thin, appear like a discoloration of the' druin"Surface, however,

the grinding effect on knife edge by material passing under it causesthe knife edge to wear faster, gradually increasing the thickness of thefilm passing under it and which on some products will scorch orcarbonize. Such burned on film on some products are wholly or partiallyremoved by the knife periodically, resulting in inferior qualityproduct, reduction in dryer capacity and frequent shut down of dryer tochange knives with complete loss of production during such shut down.

The film removed from the drying drum is usually carried away by meansof a screw conveyor and when removed in the form of a continuous sheetit must be cool or brittle enough by the time it reaches this conveyorto break up into a condition where it will be satisfactorily conveyed bythe conveyor. Moisture is continuously evaporated from the film on thehot drum surface until it is removed and on an atmospheric drum dryer aconsiderable amount of the hot vapors on the knife side of the drummoves upwardly and collects under the downwardly moving removed film,escaping from under the film at the end of the drum. These hot vaporsretard the cooling of the film. On some products air is introduced underthe film being removed but the efficiency of this air cooling is greatlyreduced due to the presence of the large amount of hot vapors trappedunder the film.

One of the principal objects of the present invention is to providemeans in the form of a plurality of knives for the removal of theproduct film and which are not subject to the above disadvantages of thesingle drum length knives now in use.

Another object is to provide such a knife which is selfalining.

Anotherobject is to provide such a knife in which expansiondue to heatwill not affect the cutting qualities of the knife.

Another object is to provide a mounting for such knife which permits ofadjustment of its angle in relation to the drum while in operation, suchadjustment permitting the sharp cutting edge to be maintained in closecontact at all times thereby to maintain optimum cutting qualities andincreasing the life and serviceability of the knife.

Another object is to provide such a knife assembly in which the frequentnecessity for regrinding of the cutting edges is materially reduced.

Another object is to provide a knife which can be replaced withoutinterrupting operation, this eliminating the necessity for shutting downthe dryer.

Another object is to provide a knife assembly which removes the film inthe form of a series of ribbons, this permitting the hot vapors toescape readily from under the ribbons.

Another object is to provide, in combination with such a knife assemblyremoving the product film in a series of ribbons, forced air coolingmeans which rapidly and effectively cool the individual ribbons tocondition the ribbons for proper transfer to the conveyor and breakingup therein, such forced air cooling means also preventing the entrapmentof any substantial amount of hot vapor at the knives and avoiding dangerof overheating of the product film through the heat retained therein.

Another object is to provide apparatus for continuously removing a filmfrom the drum, which produces a better quality and more uniform productthrough the more efficient removal of the dry product film.

Another object is to provide a knife which will closely follow the drumsurface even though the drum may not be perfectly cylindrical.

Another object is to provide such a knife which requires less pressureper inch of length than is necessary with a single knife, to maintainclose contact with the drum surface, thereby to reduce the danger ofscoring or gouging the drum surface.

Another object is to provide such a knife assembly in which thenecessity for regrinding of the cutting edges is materially reduced.

Another object is to provide such a knife assembly in which thinner andhence less expensive blades can be employed.

Another object is to provide such a knife assembly comprising aplurality of knives, in which the cutting edges of the knives can besharply reground by the operator of, the dryer on a small portable orbench grinder, thereby to eliminate the expense and delay attendant uponshipping the long knives long distances for regrinding, such shipmentbeing necessary in view of the special problems involved and the specialfacilities required for regrinding a long blade.

Other advantages and objects of the invention will appear from thefollowing description and drawings in which:

Fig. 1 is a fragmentary side elevation of one end of an atmospheric drumdryer having a knife assembly embodying the present invention.

Fig. 2 is a fragmentary vertical transverse section, partly inelevation, taken on line 22, Fig. 1.

Fig. 3 is an end view of one of the knife holders shown in Fig. 1.

Fig. 4 is a fragmentary vertical transverse section taken generally online 4-4, Fig. 1.

Fig. 5 is a fragmentary vertical enlarged transverse section, partly inelevation, taken on line 5--5, Fig. l.

Fig. 6 is an enlarged vertical transverse sectional view taken on lineB6, Fig. 1.

Fig. '7 is a fragmentary slightly enlarged ver tical sectional viewtaken on line 'l-1, Fig. 6.

Fig. 8 is a generally vertical sectional view taken on line 8-8, Fig. 6.

Fig. 9 is a vertical sectional view taken on line 99, Fig. 8.

Fig. 10 is a fragmentary side elevational view of one end of anatmospheric double drum dryer embodying the present invention, a part ofthe knife holder structure being broken away and this view in particularshowing the manner in which cooling air is supplied under pressureagainst the undersides of the strips or ribbons .being separated fromthe drying drum.

Fig. 11 is a fragmentary vertical transverse sectional view taken online H-l I, Fig. 10.

Fig. 12 is a fragmentary enlarged vertical transverse section taken online l2-l2, Fig. 10.

Fig. 13 is a fragmentary enlarged sectional view similar to Fig. 11 andshowing the parts in greater detail.

Fig. 14 is a fragmentary perspective view of the upper part of one endof the cooling air supply structure as viewed from the surface of thedrum below the knives.

Fig. 15 is a fragmentary longitudinal sectional view taken on line l5-l5, Fig. 13.

Fig. 16 is a fragmentary view, similar to Fig. 6, and showing a modifiedform of push rod for the blade in the knife holder.

The invention is shown in conjunction with a conventional atmosphericdrum dryer which can be either of a single or double drum type and whichis shown as having the usual end heads or' standards in which theopposite ends of a drying drum 2| are journaled. This drum is internallyheated in any suitable manner and the liquid or semi-liquid to be driedis applied to its descending side, the drum rotating in the direction ofthe arrows indicated in the drawings. The film or layer applied to thedescending side of the drum 2| is dried while passing under and up therising side of the drum and is then removed by the knife assemblyembodying the present invention. In accordance with the presentinvention a plurality of short, self-alining knives are arranged in twohorizontal rows or series, designated at A and B, with the knives of onerow alternating with the knives of the other row and in overlappingrelation therewith so that the enthe length of the drum surface iscontacted by the knives. Each knife operates independently and isadjustably supported so that the angle of the knife in relation to thedrum surface can be adjusted while the dryer is in operation.

The two rows of knives are supported on a hollow tube 22 which isarranged above and parallel with the drum 2| and extends beyond the endof the drum and over the upper ends of the end heads or standards 29.The opposite ends of this tube 22 are adjustably supported in bracketsindicated generally at 23, these brackets being secured upon thestandards 29, as best illustrated in Figs. 1, 2 and 11. Each of thebrackets is shown as comprising a lower block 24 which is secured to theupper face of the corresponding end head or standard 28 by screws 25 orin any other suitable manner, and as having a semicylindrioal seat 25for the corresponding end of the tube 22. This end of the tube issecured at the seat by a semi-cylindrical clamping member 28- whichembraces the upper half of this end of the tube and is secured to thesupporting block 24 by screws 29, or other suitable manner. The tube 22is preferably adjustable about its axis to different positions in itssupporting brackets 23 and is capable of being held in any of suchadjusted positions. For this purpose each end of the tube is shown ashaving a plurality of radially extending holes 39 which are arranged toregister with holes 3| and 32 extending vertically through the clampingmember 28 and supporting block 24, respectively. A tapered pin 33 ispassed through the registering holes 30 and 32 and it will therefore beseen that these tapered pins hold the tube 22 in the selected position.The purpose of the adjustment provided by the tapered pin 33 is topermit the tube 22 to be turned and held in any position for conveniencein cleaning, adjusting and inspecting the knife assembly carried by thistube. In order to prevent endwise displacement of the tube while sobeing turned after the tapered pins 33 have been removed, a collar 35 isprovided at each end of the tube 22, these collars being arranged incontact at opposing sides of the supporting blocks 24 and the supportingbrackets 23. These collars may be secured in any suitable manner as bythe set screws 36.

The two rows A and B of short, self-aiming and overlapping knives, arearranged in staggered relation and are secured to this tube 22. E01 thispurpose each knife is carried by a holder, the holders for the twoseries or rows A and B of knives being arranged to support the 'twoseries in the desired overlapping and staggered relation. As the holdersfor both series A and 'B are substantially identical in construction thesame reference numerals have been applied and the same descriptionapplies to both.

Each holder of each series is shown as having a split collar 38 whichembraces the tube 22and is clamped to the tube by a cap screw 39,- thesecap screws 39 extending through the ends of the split rings 38 anddrawing these ends together to clamp the supporting tube therebetween.Each of these clamping collars 38 is provided on its lower side with anintegral neck 4|, which is arranged on one side of the split collar andextends transversely of the axis of the tube 22 to one side thereof andis provided with an axial bore 12.

Each split collar 38 carries a rod 44 which has its upper end fastenedin its bore 42 and is adjustably secured therein by means of a set screw45 having a lock nut it, this set screw extending through the neck iiand bearing against the corresponding side of the rod it. Each rod 44 isalso held against turning by means of a key 38 arranged in correspondingkeyways provided in the rod 54 and its supporting neck 4|. A sleeve 58is mounted on each of the rods 45, this sleeve having a through bore 5|in which the rod 4- 3 is slidingly fitted and this bore being shown asprovided with annular enlargements 52 and 53 adjacent its opposite ends.Each sleeve 55 is movable lengthwise on its red 44 but held againstrotation, and for this purpose an elongated key E4: is provided which isshown as fitted in a keyway 55 in the rod 44 of substantially the samelength as the key, and also as fitted in a keyway 5i: provided in thesleeve between the annular enlargements 52 and 53 of the bore thereof.As best shown in Fig. 5, the upper end of the enlargement 52 serves as astop which engages the upper end of the key 54' and limits the downwardmovement of the sleeve 59 on its supporth'ig rod ii. To permitdisassembly of the sleeve and rod, a groove 53 is provided at the lowerend of the sleeve in alinement with the keyway 56.

A cap 60 is secured to the lower end of each of the sleeves 5G by meansof cap screws 6| or in any other suitable manner, this cap having acentral hole 62 which is in line with the axis of the rod 44 and sleeve56. In line with this hole the rod 44 is provided with an axial threadedbore 63 for receiving an adjusting screw 64, this adjusting screw beingprovided with an integral collar 55 which is interposed between thelower end of the rod 44 and the cap 60. This adjusting screw 64 isprovided with a lower threaded extension 55 which extends through thehole 62. On this extension 66 is screwed the hub 68 of a crank 69, thiscrank having a handle 10 for convenient manual manipulation thereof. Thehub 68 is further fastened by means of a pin 1|, this pin serving tohold the cap 60 in closely fitted relation to the integral collar of thescrew 64 and to the hub 68 of the crank 69 so that the screw 6d isrotatably mounted on the cap (ill but is held against substantial axialmovement relative thereto. It will therefore be seen that turning eachcrank 69 serves to move the corresponding sleeve 50 axially relative toits supporting rod 44. It will be noted that the upward movement of thesleeve in this direction is limited by the engagement of the collar 65with the end of the rod 44 and that the downward movement of the sleevein this direction is limited by the engagem'ent of the upper end'of thekey 5 |with the upper end wall of the enlargement 52 of the sleeve bore54.

On the side of the sleeve 50 toward the drum 2I are two projections 75and I6, each provided with a hole drilled therethrough parallel with thedrum 2I. In the projection I5 is arranged a knife holder swivel pin I8which turns freely in this projection and is held in place by nuts I9,as best shown in Fig. 7. The head 80 of this knife holder swivel pin "I8is shown as being cylindrical in cross section and is provided with aslot BI which extends transversely of the axis of the knife holderswivel pin, as best shown in Figs. 4, 6 and 7 In addition, this head iscounterbored, as indicated at 82 and 83, at the opposite ends of thisslot 8|. The slot 8I so counterbored receives a knife holder rod 85which is shown as provided with a handle 88 at its outer end and alsowith an enlarged cylindrical portion 83 which fits the counterbore 82.On the opposite side of the head 80 a sliding sleeve 89 is mounted onthe knife holder rod 85, this sleeve having an end 90 which is adaptedto fit into the other counterbore 83. When so fitted the sleeve 89 isheld against axial displacement by a setscrew 9|.

It will be seen that by loosening the setscrew 9| the end 98 of thesleeve 85 can be slipped out of the counterbore 83. This permits theknife holder rod 85 to be withdrawn so as to free the enlargement 88from the counterbore 82. In this position the knife holder rod 85 can beremoved sidewise from the slot 8! so as to be completely freed from thehead 80 of the knife holder swivel pin I8.

The inner end of the knife holder rod 85 carries a knife head, indicatedgenerally at 95, and which generally is in the form of a safety razorhead. As best shown in Figs. 6-9 this head is made of two pieces, onepart 98 being in the form of a backing frame to which the correspondingblade 98 is held by a clamping plate 99. The backing frame 95 isprovided with an internally threaded neck I into which the threaded endof the knife holder rod 85 is screwed, these parts being held againstdisplacement by a lock nut I8I. The backing frame 96 is elongatedparallel with the drum and is formed to provide a flange I02 along itsupper edge and against which the upper edge of the clamping plate 99 isdisposed. This clamping plate is secured in position by a plurality ofscrews I03 which anchor in the backing frame 96 so that the blade 98 issecurely clamped between this backing frame and the clamping blade asbest shown in Figs. 6 and 9. In order to hold the clamping blade 99 inparallel relation with the blade 98 a plurality of screws I04 areprovided which extend through the backing frame 95 into abutment withthe inner face of the clamping plate 99 at its upper end, these screwsprojecting outwardly from the drum side of the backing frame a distanceequal to the thickness of the blade 98 and thereby serving to space theupper end of this backing plate the thickness of the knife blade awayfrom the backing frame.

The upper side of the backing frame 98 is provided with a fiange H15projecting upwardly therefrom and in a direction away from the drum 2i,this flange forming a socket I06 for the reception of the rounded end ofa push rod I08. This push rod is provided with an end knob I09 at itsouter extremity and is threaded intermediate its ends, as indicated atH0. This threaded part H0 of each push rod is screwed into the 8 squarehead III of a bolt H2, this bolt being rotatably mounted in theprojection 16 of the sleeve 50. This bolt is held against displacementby a pair of nuts I I3, as shown in Fig. 1.

It will be seen that essentially each individual blade mounting is atriangular truss. The triangle is defined by a cantilever beam in theform of the sleeve 50, an adjustable tension member, in the form of theknife holder rod 85, hinged to the end of the cantilever beam 50, anadjustable strut, in the form of the push rod I08, hinged to anintermediate point along the cantilever beam 50, said strut I08 andtension member 85 converging toward the apex of the triangular truss, ablade clamp secured to the tension member 85 and bearing on the end ofthe strut I08 at the apex, and means for varying the length of thecantilever beam 50 between its support and the hinge to the adjustablestrut I08.

Means are provided for limiting the swinging movement of each push rodI08 when released from the socket I06 sufficiently for the rounded endof the push rod to clear the projections I05. For this purpose eachsleeve 50, Fig. 4, carries a stop pin H4 which is shown as screwed intothe side of the sleeve 50 and arranged above its companion knife holderrod 85 sufficiently far to clear the knife holder rod 85 and handle 86when the push rod I08 is resting on the stop pin I I4.

It is also desirable to be able to hold each knife holder in an elevatedposition clear of drum surface 2I when not operating or to prevent theknife holders from piling up against one another when the main tube 22is loosened and turned in its brackets 23 for cleaning or any otherpurposes. To this end the slotted head which supports each knife holderrod is provided with a bore H6 which contains a spring loaded detent pinH8, as best shown in Fig. '7. This pin is provided with an operatingplunger I I9 which projects outwardly from the head 80 and its springI20 urges the pin against the adjacent face of the enlargement 15 of thesleeve 50. This pin is adapted to enter a latching hole I2l which islocated as shown so that when the knife holder is swung about its knifeholder swivel pin 18 in raising the knife holder, the spring loadeddetent pin H9 enters the hole I2I and holds the knife holder in anelevated position until it is released by withdrawing the plunger H8 ofthedetent pin.

The material removed by the knives falls into a side conveyor I38comprising a trough I3I arranged alongside the drying drum andcontaining a screw or helix conveyor I32 which is rotated so as to breakup the material and convey it to an end of the trough I3l. An innerapron I33 is provided along the inside of the trough and an outer apronI34 is provided along the outside of the trough so as to direct fallingmaterial into the trough.

On materials removed by the knives in the form of flakes, crystals orpowder, the upper edge of the inner apron I33 is arranged as close aspossible to the drying drum 2I. The dried product, in flake, crystal orpowder form, will then roll down over the drying film on the upwardlymoving drum surface and drop into the side conveyor I30. Such materialsconvey readily without any additional air cooling and if cooling shouldbe necessary to prevent overheating in storage, etc. it is usually doneafter the material leaves the dryer. Where there are objections to thedry material rolling down over the upwardly moving and drying film theposition of '9, "the knives on the drum surface can be lowered to apoint where the material will fall away from the 'drum as removed, thatis, the knives are located at any point along the drum periphery to suitremoval of the product being dried.

On products removed from the drum in the form of solid continuousribbons, the physical character of the product determines the coolingprocedure; on products such as dried skimmed milk, thedry film asremoved does not adhere to the knife edges and large amounts of vaporare liberated from the drying'film on the up- Wardly moving drumsurface. These liberated vapors, mixed with some natural circulation of.

air, causes the thin films to actually float on those vapors and airmixture and in spite of the heat it "cools sufficiently by the time itreaches the screw conveyor to permit the material to be handled bytheconveyor screw I32 without any additional cooling.

Other products such as distillery slop or stillage, when removed by theknives and in a hot state, are soft, somewhat sticky and temporarilyadhere or gather in front of the knives so that the film leaving theknives is considerably thicker than the film on the drum surface. Thus,the periphery speed of the drum may be three times the speed of the filmleaving the knives, and the film leaving the knives under theseconditions would theoretically be three times as thick as the film onthe drum. The hot soft film so retarded and thickened on leaving theknives, unless'cooled quickly has little tensile strength, and tends toretain its heat to a point of overheating which on most products reducesits value. Thus the hot soft retarded film at knife, unless cooledquickly, has insufncient strength to properly support the weight of thehanging film and pull exerted upon it by the side conveyor, tearingeasily and intermittently at the knife and dropwith the presentinvention, a blast of cool air is introduced under each ribbon or film ashort distance "below each knife, this blast of air cooling the ribbonfilm sufficiently to toughen the film and prevent it from being tornfrom the knife. These blasts of air also cool the ribbons suffi'cientlyto prevent overheatin after leaving the drum surface and also acceleratethe overall cooling. These blasts of air also aid the movement of theribbons and float the ribbons and accelerate their cooling on their wayto the screw conveyors I30. The means for effecting this cooling, inaccordance with the present invention, are preferably constructed asfollows:

The numeral I35 represents an air supply pipe which is supported fromthe end heads or stand ards '20 of the dryer in any suitable manner, asby the brackets I36, and is arranged alongside the'drum above the innerapron I33 for the side conveyor I30. To the inner side of this airsupply pipe I35 is suitably secured a vertical metal sheet I31, and tothe outer side of this air supply pipe I35 is similarly secured an outercurved metal sheet; I38. Intermediate these two metal sheets, a thirdcentral metal sheet I39 is secured to the airsuppl pipe I35 so as toform an inner manibest shown in Fig. 14.

fold chamber I40 and an outer manifold chamber MI. The inner verticalmetal sheet I31 extends downwardly a short distance from the air supplypipe I and is formed along its lower horizontal edge with an outwardlyextending horizontal lip or flange I42 on which the upper flanged edgeof the inner apron I33 for the side conveyor re movably rests and thisinner vertical metal'sh'eet I31 extends upwardly a short distance fromthe air supply pipe I35 and is secured to the rear edge of a horizontaltube plate I43 which is secured at its front edge to the central metalsheet I39 so as to enclose the top of the manifold chamber I40. The endsof chambers I and MI are enclosed by end sheets I44 which conform to andare secured to the opposite end'edges of metal sheets I3! and I39 andtube plate I43, each of these end sheets I44 extended forwardly toengage the rear face of the outer metal sheet I38 and downward to engagesupply pipe I35 as best shown in Figs. 13 and 14. The opposite ends ofouter metal'sheet I38 project beyond these end sheets I44 and aresecured to end sheets or flanges I45 which project inwardly from theextremities of the outer metal sheet I38 and are arranged alongside theinner or opposing faces of the main end heads or stands 20 of the dryer.

The entire air supply manifold structure as above described isadjustable toward and from the drying drum 2|, For this purpose the airsupply pipe I35 is capable of rotating in its brackets I35 and anL-shaped metal arm I46 is welded to each end sheet or flange I45 andcar'- ries a generally horizontal adjusting screw I48, as The inner endof each of these adjusting screws I43 is positioned to bear against thevertical side face of the corresponding main end head or stand 20 of thedryer and since the drying drum ZI is journaled in these end heads orstands 2:; of the dryer it will be seen that screwing in the adjustingscrews I48 will move the upper end of the air supply manifold structureaway from the drum 2| to effect any I desired relative spacing thereof.

The inner manifold chamber I 33 is supplied with air from the supplypipe I35 through a plurality of orifices I52 and the outer chamber MI issimilarly supplied with air from the air supcorresponding orifices inthe air supply pipe I35.

Each of these slides is shown as being manually adjusted by means of anupstanding flange I56 at one end thereof and. as secured to the airsupply pipe I35 by screws I58 extending through slots I59 provided inthe slide.

The metal sheets I38 and I39 are curved and arranged so that their upperextremities ar arranged adjacent the knife holders. The outer metalsheet I38 is provided at its upper endwith a series of spacedrectangular extensions I60 which project upwardly between the knifeholders of the lower series B and to a position immediately adjacent theknives 08 of the upper series A. This outer metal sheet is also providedwith a series of downwardly and outwardly projecting louvers I 8i whichare arranged in spaced relation over its entire surface, as best shownin Fig. I0. These louvers ItI are struck from the outer metal sheet "toprovide an" escape openings therein, the

streams of air from these openings beingdeflecte'd' downwardly by theselouvers NH. The intermediate metal sheet I39 is provided with anoutwardly and upwardly extending flange I52 along its upper edge, theextreme forward edge of which flange I62 is welded or otherwise suitablysecured to the inner face of the outer metal sheet I38 so as to enclosethe upper part of the chamber I4I.

To facilitate the movement of the ribbons or strips of material removedby the lower series of knives B to the exterior face of the outer metalsheet I38 and to the zone of action of the stream of air issuingfrom'under the louvers I8 I this outer metal sheet I38, between itsupwardly extending rectangular extensions I00, is flanged inwardly, asindicated at I63, these flanges being directed toward the blades 98 ofthe lower series B of knives, as best shown in Fig. 13.

A feature of the invention resides in the provision of an individualblast or jet of air for each strip removed by each blade 58: of theseries A and B. This blast or jet of cooling air is directed against theunderside of the strip or ribbon leaving each knife and to this end aseries of vertical open ended air tubes I65a, I651) are mounted on theunder side of the central sheet I39. The lower end of each of thesetubes I65a, I652) is connected to a screw fitting I66 which is screwedinto a vertical threaded opening provided i the tube plate I43. It willtherefore be seen that air from the manifold chamber I49 escapes throughthis series of tubes I85a, I852). Each of the tubes I 65a is arrangedunder a corresponding knife holder 95 of the series A and each of thetubes I05b is arranged under a corresponding knife holder 95 of theseries B, the series of tubes 105a thereby being in alternation with theseries of tubes I651). The tubes I55a, I65?) can be held in position inany suitable manner as by the U- shaped sheet metal holders I68.

The tubes I65a are longer than the tubes H552) and the upper end of eachof the tubes I651: is arranged under the corresponding rectangularextension I60 of the outer metal sheet I38, this upwardly directed openend of such tube I65a thereby discharging a stream of cooling airupwardly along the underside of this rectangular extension I50 againstthe under side of the ribbon or strip of material being removed by thecorresponding blade 98 and passing from this blade over the rectangularextension I50 and down the exterior of the outer metal sheet I38. Theshorter tubes I65b are arranged to discharge upwardly against the undersides of the lips I53 and hence against the under sides of the strips orribbons of material being removed by the lower series B of knives. Theair so discharged by the tubes I85a and I652) serves to quickly cool andfloat the strips or ribbons so removed for delivery onto the rectangularextensions I60 and lips I53, and the mixture of cool air from the tubesand hot vapors escapes freely from under and among the strips so thatthere is no pocketing of a body of hot vapors and air mixture underthese ribbons or strips.

As these strips move down the exterior face of the outer metal sheetI38, they are further floated and aerated by the streams of cooling airissuing from the openings provided by the louvers I6I so that the stripsare air-cooled in their travel down this outer metal sheet 138 and henceproperly conditioned before being deposited in the side conveyor I39.

In Fig. 16 is illustrated a modified form of push rod for the blades andwhich is characterized by being resiliently extensible so as to exert anadjustably resilient pressure against the blade holder and therebypermit greater freedom of the blade in following, say, an out of rounddrying drum. The push rod structure shown in Fig. 16 is designed tosupplant the form of push rod I08 shown in the other figures of thedrawings and for this purpose comprises a tube I10 which is threaded atone end, as indi-- cated at I1I, in order to screw into the threadedaperture through the nut III of the bolt H2 in the same manner as withthe push rod I08. An adjustable knob I12 is shown as secured to theouter end of the tube I10 by set screws I13 and in the opposite end ofthis tube is arranged a bushing I14 which slidingly receives a rod I15,the free end of this rod being rounded to fit into the socket I06 formedby the flange I05 of the blade holder 95, in the same manner as with thepush rod I08. Within the tube or sleeve I10 the rod I15 is provided withan enlargement or collar I16 which slides within the bore of the tubeI10. A helical compression spring I18 is interposed between this collarI16 and the knob I12 so as to normally urge the rod I 15 axially towardthe blade holder 95. The rod I15 extends through an opening in the knobI12 and is threaded, as indicated at I19, to receive a Wing nut I whichdue to urging of the compression spring I18 prevents rod I15 from movingforward beyond a set point.

It will be seen that the pressure exerted by the rod I15 against theblade holder 95 canbe adjusted by turning the knob I12 in acorresponding direction to move the sleeve I10 lengthwise in the nutIII. At such adjustment the helical compression spring I18 will exert apredetermined pressure against the socket I06 of the blade holder so asto impress a corresponding pressure against the blade 98. In the eventthat the drum 2| is out of round, the push rod I15 can move rearwardlyagainst the resistance of the helical compression spring I18, thereby topermit the blade 98 to breathe or move in respect to the undulatingsurface of the drying drum 2|. Since in other respects the structureshown in Fig. 16 is identical to that shown in Figs. 1-15, the samereference numerals have been employed.

In the operation of the drum dryer shown a liquid or semi-liquid productfilm is applied to the descending side of the internally heated rotatingdrum 2|, this film being carried around the underside of the drum and upits rising side to the two series A and B of knives. During thismovement of the film on the heated drum 2 I, moisture is evaporated fromthe film and since this film is continuously being applied andcontinuously being removed by the knives, the opera ation of the dryeris continuous. This film first encounters the blades 98 of the lowerseries of knives designated at B, this series of knives extendinglengthwise of the drum 2| and these knives being in spaced relation,these knives thereby removing a part of the film in the form of. aseries of spaced ribbons. The portions of the film on the drying drum 2|passing through the spaces between the knives 98 of the lowerseries Bcontinue upwardly until they are engaged by the blades of the upper orsecond series of knives designated at A. The lengths of the blades 98 ofthe two series A and B of knives are such as to overlap and hence thestrips on the drum passing between the blades 98 of the lower series Bof knives are completely removed 13 in the form of ribbons by the secondseries A of these knives.

These ribbons so removed by both series A and B of knives curl outwardlyover the air supply manifold and slide downwardly along the outer metalsheet or plate I38 of this air manifold. As best shown in Figs. 11 and12, this outer "sheet I38 of the air supply manifold is curved andextends downwardly and outwardly to lead the ribbons so removed by theknives into the space between the aprons I33 and I34 of the screwconveyor I32. This screw conveyor vpicks up these. ribbons and conveysthem lengthwise to one end of the conveyor trough I3I, this screwconveyor I 32 serving to break up the ribbons into pieces capable ofsubsequent handling in a fiaker or the like.

With many materials in order to condition the ribbons so removed by theknives it is necessary to provide auxiliary cooling means for reducingthe temperature of the material removed from the drum U by the blades98. This auxiliary cooling is performed by the air supply manifold whichfunctions as follows:

In its operation cooling air under pressure isintroduced into one end ofthe air supply pipe 35.from which it escapes through the two series ofopenings I52 and I53. The amount of air so escaping from these openingsis under control of the valve slides I54, these valve slides havingreadily accessible finger pieces I56 at one end as shown in Figs. and15. The longitudinal adjustment of the slides I54 adjusts the effectivesizes of either series of openings I52 or I53, thereby to adjust theamount of air admitted to the chambers I40 and MI. The chamberI40communicates with the interior of the two series of tubes H551; and I05b. The tubes IE5!) are relatively short and each delivers the airagainst the under side of the corresponding lip or flange I63. The tubesI65a. are relatively long and each delivers an upwardly directed streamof air under the corresponding rectangular extension I00.

Since theribbons or strips of material removed by the series A of knivestravel over the rectangular extensions I60, and since the ribbons orstrips of material removed by the lower series I B of knives travel overthe flanges I63, it will be seen that an individual blast of air fromthe corresponding tube I65a or I55b impinges against the underside ofeach band or ribbon being removed from the drum and serves to cool andtoughen each band or ribbon as well as to lift or fioat the ribbon andinsure smooth delivery of these ribbons to the outer metal sheet I38 ofthe air supply manifold. It will also be seen that since the productfilm is removed from the drum in the form of strips or ribbons theblasts of air so directed by the tubes I65a, I65b against the undersides of these ribbons readily escape through the spaces between theseribbons so that there is 'no pocketing of vapor-laden air under the filmbeing removed from the drying drum as would be the case if this filmwere removed ina s ngle continuous sheet.

As the ribbons continue their downward journey over the outer side plateI38 of the air supply .manifold they pass over the louvers I6! whichdeflect further jets of cool air against these ribbons. This air issupplied from the chamber MI through the openings provided in formingthe louvers IGI, as best shown in Figs. Hand 13, and the jets of air sodelivered through. these openings and deflected downwardly by thelouvers IBI provide for further cooling of the film to insure theirproper conditioning for ready handling by the screw conveyor.

The pressure of the knife blades of either series A or B can readily beadjusted to suit the particular product being removed from the drum.This pressure is individually adjusted for each knife holder and isefiected by turning the hand wheels I99. Turning this hand wheel foreach knife holder 95 screws down or backs up the threaded connectionbetween the corresponding push rod I08 and the nut III supporting thispush rod. This longitudinal movement of the push rod I08 increases ordecreases the pressure exerted by the push rod on the upper side of itsknife holder s5 and thereby increases or decreases the pressure of thesharpened edge of the knife blade 9-5 against the surface of the dryingdrum 2 I, the rod 85 for each knife holder being free to oscillate aboutits pivot 78. In the event the form of push rod shown in Fig. 16 isemployed the knife blade $8 is yieldingly held against the drum 2i bythe reactance of the spring I78 which tends to expand longitudinally thepush rod shown in this figure.

A worn knife blade can be replaced very rapidly by the followingprocedure and without shutting down operation of the dryer.

With a knife holder 95 whose blade is worn, the operator grasps handwheel I08 turning it counterclockwise a few turns to back up the pushrod I03 far enough to free it from socket I05 and flange I05 on knifeholder 95 dropping the push rod I08 onto stop pin H4.

The operator then grasps the handle '88 of this rod 85 and moves itdownward, thereby to elevate the knife holder 95, until the springloaded detent M8, operated by the plunger I I9, snaps into the recessI2I provided in the ear or extension 15 on the sleeve 55 and whichrotatably supports the head 33 which carries the knife holder rod 85.With one hand on the handle 85 the operator loosens the thumb screw SIand pushes the collar 89 two inches or so toward the knife holder 55 andthen tightens this thumb screw 9| to keep the. collar 39 from sliding.He then pulls on the handle 85 until the collar 58 is removed from therecess 82 and clears the head '80 of the swivel pin 18. The operatorthen removes the rod 85 sideways from the slot 0| thereby freeing theentire knife holder assembly from the swivel pin structure I8, 80.

With another knife holder assembly containing a sharp blade 93available, the replacement can easily be effected by a reverse of theabove procedure. Thus the operator takes the fresh knife holder assemblyand moves the collar 89 an adequate distance onthe rod 85 towardtheknife holder 95 and tightens the thumbscrew 9| so that this collar willnot slide on the rod. He then slides the shaft 85 between its collars 88and 39, sideways into the slot 8! in the head 89 of the swivel pin I3.He then pushes forward on the rod 35 until the collar 08 enters thecounterbore-B2 as far as it will go and loosens the thumb screw 9i andmoves the opposite collar 89 into the counterbore 83 and tightens thethumb screw GI.

He then turns the crank '69, a few turns clockwise so as to slide themovable sleeve 50 upwards as far as it will go, this upward movement ofthis sleeve being effected through the screw as and its collar 05. Thissets the pivots l9 and M2 for the rods and I08, respectively, so that'atthe start of use the knife blade 98 will operate at its minimum angle.The operator,

15 with one hand on the handle 86, then pulls out the small plunger l19, this freeing the detent l 83 from the hole 12! and permitting thehead 8", and the rod 85 carried thereby, to swivel about the axis of thepin 18. He then slowly raises the handle 83 to lower the knife blade 98to engage the drum 2!. Since the swivel pin 18 for the head 89 turnsfreely in its mounting on the sleeve 59 and the rod 85 with its collars5'3 and 89 turn freely in this head 80 of the swivel pin 38, it will beseen that the knife blade 93 automatically alines or fits itself to thesurface of the drum-2 l.

The operator then raises the handwheel 199 of the push rod U38 to alinethis push rod with the socket H35 of the knife holder 95 and turns thehandwheel I99 clockwise. This moves the push rod, through its threadsIll), longitudinally to bring its lower end into contact with the socketI06 and to exert the desired pressure on the blade 93 through the knifeholder 535.

While the above description appears lengthy, the time required to make acomplete knife change is very short. By actual timing it requiresapproximately a half minute to remove a worn knife and replace it with anew knife as described.

It will also be seen that the angle of each knife blade 93 withreference to the surface of the drum 2i can quickly be altered. This isimportant in extending the life of the knife blades 58. Thus, a fresh orsharp knife blade is started at the minimum angle relative to thetangent at the line of contact of the knife with the drum surface and issubjected to light pressure contact against the drum surface. In use aflat is worn on the knife blade, this flat being in contact with thedrum surface and growing with wear. When the wear or increase of theflat surface in contact with the drum becomes suiiicient to impairproper removal of the product film from the drum, the knife angle, withreference to the tangent at the line of contact of the knife blade withthe drum surface, is increased slightly so as to bring the knife bladetoward a radial position. This slight change in angularity of the knifemoves the flat worn at its edge away from the drum surface and leavesonly the sharp cutting edge in contact with the drum surface so that theproduct film is again efiectively removed with light knife bladepressure. As a second flat wears on the newly positioned knife blade,its angle can be again increased to move this second flat away from thedrum surface and again leave only the sharp cutting edge of the knife incontact with the drum surface.

This increase in the angularity of each knife blade with reference tothe drum surface can readily be effected by turning the crank 69, 10 tolower the sleeve 50 supporting the knife blade. This downward movementof the sleeve 50 is effected through the screw 64 and its collar 65. Thedownward movement of this sleeve lowers the pivot points 78, H2 aboutwhich the knife holder rods 85 and H18 swivel and hence it will be seenthat this increases the angle of the knife blade 98 relative to the drumsurface to so increase the effective life of the blade.

From the foregoing it will be seen that the present invention provides asimple and effective means for removing the film from the drum of a drumdryer and for air cooling the same to place it in proper condition forhandling by the conveyor and provides a knife assembly in which theblades are self-alining, readily adjusted to 16 obtain the maximum life,and are readily removed, reground and replaced when required.

I claim:

1. Apparatus for removing the product film from the surface'of arevolving drum, comprising a plurality of knife blades arranged alongthe periphery of said drum and with their cutting edges in engagementtherewith, and means forming the sole support for at least one of saidknife blades, comprising a rod mounted adjacent the periphery of saiddrum and parallel with an adjacent tangent thereof, a sleeve slidablymounted on said rod for non-rotative movement lengthwise thereof, meansfor adjustably positioning said sleeve lengthwise of said rod, an armpivoted exclusively on said sleeve and projecting toward said drum, asupporting head connected centrally to said one of said knife blades andmounted on the end of said arm adjacent said drum. and in position toengage the periphery thereof, and a member movably mounted on saidsleeve and urging said one of said knife blades into engagement with theperiphery of said drum.

2. Apparatus for removing the product film from the surface of arevolving drum, comprising a plurality of knife blades arranged alongthe periphery of said drum and with their cutting edges in engagementtherewith, and means forming the sole support for at least one of saidknife blades comprising a rod mounted adjacent the periphery of saiddrum and parallel with an adjacent tangent thereof, a sleeve slidablymounted on said rod for non-rotative movement lengthwise thereof, meansfor adjustably positioning said sleeve lengthwise of said rod, an armpivoted exclusively on said sleeve and projecting toward said drum, asupporting head connected centrally to said one of said knife blades andmounted on the. end of said arm adjacent said drum and in position toengage the periphery thereof, and means on said sleeve and urging saidone of said knife blades into engagement with the periphery of said drumcomprising a longitudinally adjustable push rod mounted on said sleeveat a place in spaced relation to the pivotal mounting of said arm andhaving one end connected to urge the end of said arm adjacent said drumtoward said drum.

3. Apparatus for removing the product film from the surface of arevolving drum, comprising a plurality of knife blades arranged alongthe periphery of said drum and with their cutting edges in engagementtherewith, and means supporting at least one of said knife blades,comprising a supporting rod arranged adjacent the periphery of said drumand parallel with an adjacent tangent thereof, a sleeve slidably mountedon said rod for non-rotative movement lengthwise thereof, means foradjustably positioning said sleeve lengthwise of said supporting rod, aswivel pin mounted on one end of said sleeve to swing about an axisgenerally parallel with the axis of said drum and having a head, a bladeholder rod detachably secured to said head to extend transversely ofsaid swivel pin and toward said drum, a holder for said one of saidknife blades mounted on the end of said rod adjacent said drum and inposition to engage the periphery thereof, a push rod pin rotatablymounted on the opposite end of said sleeve to swing about an axisgenerally parallel with the axis of said drum and having a head, saidlast head being provided with a threaded hole extending therethroughtransversely of the axis of said push rod pin, a threaded push rodscrewed in said hole. one end of said push rod being operativelyconnected to said blade holder rod to urge said one of said blades intoengagement with the periphery of said drum.

4. Apparatus for removing the product film from the cylindrical surfaceof a revolving drum, comprising a holder arranged adjacent saidcylindrical surface, a cantilever beam carried by and projecting fromsaid holder, a tension member hinged to the outer end of said cantileverbeam and projecting toward said cylindrical surface. a longitudinallyadjustable strut hinged to an intermediate point along said cantileverbeam and projecting toward said cylindrical surface in convergingrelation to said tension member, a knife head secured to the end of saidtension member adjacent said cylindrical surface and bearing against theadjacent end of said strut, a knife blade carried by said knife head andhaving a cutting edge engaging said cylindrical surface in opposition toits movement, and a member secured to said cantilever beam and operablefor varying the effective length of said cantilever beam between saidholder and its hinged connection with said strut.

5. Apparatus for removing the product film from the periphery of arevolving drum, comprising a holder mounted adjacent the periphery ofsaid drum, a swivel pin mounted on said holder to swing about an axisgenerally parallel with the axis of the drum and having a head, saidhead being provided with a transverse slot, a rod fitted in said slotand extending transversely of the axis of said swivel pin and towardsaid drum, a member releasably retaining said rod in said slot, and aknife blade mounted on the end of said rod adjacent said drum and havinga cutting edge engaging the periphery thereof in opposition to itsmovement.

6. Apparatus for removing the product film from the periphery of arevolving drum, comprising a holder mounted adjacent the periphery ofsaid drum, a swivel pin mounted on said holder to swing about an axisgenerally parallel with the axis of the drum and having a head, saidhead being provided with a transverse slot, a rod fitted in said slotand extending transversely of the axis of said swivel pin and towardsaid drum, said head being provided with retaining sockets at oppositeends of said slot, a collar fixed to said rod and fitting one of saidsockets, a collar slidable on said rod and fitting the other of saidsockets and releasably secured therein, and a knife blade mounted on theend of said rod adjacent said drum and having a cutting edge engagingthe periphery thereof.

7. Apparatus for removing the product film from the periphery of arevolving drum, comprising a holder mounted adjacent the periphery ofsaid drum, a plurality of knife heads, a knife blade mounted on each ofsaid knife heads and having their cutting edges arranged in oppositionto the moving surface of said drum, a supporting arm secured to each ofsaid knife heads, a pivotal connection between each of said supportingarms and said holder, and a manually releasable detent interposedbetween each of said supporting arms and said holder and arranged tolatch said arm in an inoperative position against pivotal movement.

8. Apparatus for removing the product film from the periphery of arevolving drum, comprising a holder mounted adjacent the periphery ofsaid drum, a swivel pin mounted on said holder to swing about an axisgenerally parallel with the axis of the drum and having a head, a roddetachably secured to said head to extend transversely of said swivelpin toward said drum, a knife blade mounted on the end of said rodadjacent said drum and having a cutting edge engaging the peripherythereof in opposition to the movement thereof, a pin rotatably mountedon said holder in a position to one side of said rod and to swing aboutan axis generally parallelwith the axis of said drum and having a head,and a push rod extending through said last head transversely of the axisof its pin and adjustable longitudinally therein, the end of said pushrod adjacent said drum being operatively connected with said knife bladeto urge its cutting edge into firm engagement with the periphery of saiddrum.

CHARLES O. LAVETT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Date

